Method of applying powder to a substrate during a continuous process

Abstract

A recirculating powder applicator includes an applicator body having an inlet on an upstream surface and an outlet on a downstream surface, wherein the inlet and outlet define a passage that extends transversely through the thickness of the applicator body, a powder conduit, an air inlet, an exhaust aperture located on one of the upstream or downstream surfaces, and a circulation chamber located on the interior of the applicator body. The powder conduit and air inlet are in fluid communication with the passage and the passage is in fluid communication with the circulation chamber. A method of applying powder to a substrate during a continuous process includes using a recirculating powder applicator.

What is claimed is: 
     
       1. A method of applying powder to a substrate during a continuous process, the method comprising the steps of:
 providing a continuous run of a substrate through a powder applicator; 
 providing a metered flow of powder onto the substrate through a powder conduit of the powder applicator, wherein a first portion of the powder is deposited on the substrate from the powder conduit; 
 providing between 15 and 100 psi of air through an air inlet of the powder applicator simultaneously with the providing the metered flow of the powder, wherein the air recirculates a second portion of the powder within a circulation chamber of the powder applicator and wherein the second portion of powder is deposited on the substrate after being recirculated; and 
 exhausting the air through an exhaust aperture located within the circulation chamber of the powder applicator, wherein the exhausted air contains less than 5% of the powder dispersed within the air. 
 
     
     
       2. The method of  claim 1 , further comprising the step of achieving equilibrium between the first portion of deposited powder, the second portion of recirculated powder, and the powder in the exhausted air, such that the first and second portions of powder and the powder in the exhausted gas equal the metered flow of powder on the substrate. 
     
     
       3. The method of  claim 1 , wherein the circulation chamber is shaped like a nautilus. 
     
     
       4. The method of  claim 1 , wherein the circulation chamber includes a depression around the exhaust aperture. 
     
     
       5. The method of  claim 4 , wherein the depression is toroidal in shape. 
     
     
       6. The method of  claim 1 , wherein the powder is a superabsorbent polymer. 
     
     
       7. The method of  claim 6 , wherein the substrate is a run of cable core and partially formed armor. 
     
     
       8. A method of applying a moisture barrier between a cable core and an armor, the method comprising the steps of:
 receiving a run of cable core from a cable core payoff; 
 receiving a run of armor from an armor payoff; 
 forming the armor at least partially around the cable core during a first armor forming step; 
 applying a superabsorbent powder to the cable core and an interior surface of the partially formed armor, wherein the powder is applied using a powder applicator that comprises:
 an applicator body including an inlet on an upstream surface and an outlet on a downstream surface, wherein the inlet and outlet define a passage that extends transversely through the thickness of the applicator body; 
 a powder conduit; 
 an air inlet; 
 an exhaust aperture located on one of the upstream or downstream surfaces; and 
 a circulation chamber located on the interior of the applicator body and including a depression formed around the exhaust aperture; 
 wherein the powder conduit and air inlet are in fluid communication with the passage and wherein the passage is in fluid communication with the circulation chamber; and 
 
 completing the forming of the armor around the cable core during a second armor forming step such that the armor surrounds the cable core. 
 
     
     
       9. The method of  claim 8 , further comprising the step of extruding a jacket around the armor. 
     
     
       10. The method of  claim 8 , wherein the cable core contains a plurality of bundles of optical fiber elements. 
     
     
       11. The method of  claim 8 , wherein the applying a superabsorbent powder step further comprises the steps of:
 providing a metered flow of powder onto the cable core and armor through a powder conduit of the powder applicator, wherein a first portion of the powder is deposited on the cable core and armor from the powder conduit; 
 providing between 15 and 100 psi of a gas through an air inlet of the powder applicator simultaneously with the providing a metered flow of powder step, wherein the gas recirculates a second portion of the powder within the circulation chamber of the powder applicator and wherein the second portion of powder is deposited on the cable core and armor after being recirculated; and 
 exhausting the gas through an exhaust aperture located within the circulation chamber of the powder applicator, wherein the exhausted gas contains less than 5% of the powder dispersed within the gas. 
 
     
     
       12. The method of  claim 11 , further comprising the step of achieving equilibrium between the first portion of deposited powder, the second portion of recirculated powder, and the powder in the exhausted gas, such that the first and second portions of powder and the powder in the exhausted gas equal the metered flow of powder on the substrate.